In modern computing hardware, e.g., a disk and a random access memory, encoded magnet bits, manifested as the magnetization directions of ferromagnets (FMs), are utilized to write, store, and retrieve information. Controlling the magnetization direction, via interactions between spins and charges, is crucial for spintronics devices and remains a focus of major research efforts.
Conventionally, magnetization controlling, i.e., switching of magnetization directions, is achieved via a current-induced spin transfer torque (STT) that requires a spin polarizer in a spin valve or magnetic tunnel junction structure.
Recently discovered spin-orbit torque (SOT) in a FM layer adjacent to a metal layer has opened a new era of spintronics. SOT allows low power magnetization controlling and fast motion of a domain wall, an interface separating magnetic domains. A working scheme based on SOT brings high stability, simplicity, and scalability, making it attractive to incorporate the technology into the next generation spintronics devices.
There is a need to develop high-performance spintronics devices utilizing SOT in commercial applications.